FREMONT, California (AP), Apr 14 - Five men have been charged in a $37 million armed heist at a technology firm that authorities called the largest computer chip robbery ever in the San Francisco Bay area - one of America's tech hotspots.

The men were arrested after as many as 15 people armed with rifles and handguns and wearing gloves and masks stormed a loading dock at Unigen Corp. on Feb. 27.

The robbers tied up several employees and locked them in a room before spending a half-hour loading flash memory chips into a truck.

Other suspects were still being sought. Authorities declined to say what led authorities to the five men who were arrested.

Most of the chips were later found inside a small storage garage, although investigators said some ended up in Asia.

They also face an enhancement known as excessive taking, which reflects the value of the components taken, said Michael Sterner, director of the Rapid Enforcement Allied Computer Team, a task force that investigated the case.

The defendants were arrested over a 10-day span that ended on April 7. They were being held without bail and were expected to be assigned attorneys and enter pleas on Friday during a court appearance.